1. Technical Field
The invention relates generally to cementitious block or concrete masonry units (CMUs) and a mixture of materials forming the CMU. More particularly, the invention relates to CMU material which provides improved characteristics such as water repellency. Specifically, the invention relates to such a CMU material which includes spent blasting abrasives of a suitable size and a sufficient amount to produce a highly desirable CMU having increased compressive strength and substantially improved water repellency and other characteristics.
2. Background Information
Concrete masonry units (CMUs) have long been used in the construction industry to provide a relatively inexpensive and strong building unit, especially in comparison to the use of bricks which typically have a higher cost due to the necessity of firing the bricks to fairly high temperatures. While CMUs have been widely used, there is still room to improve on the various characteristics thereof. CMUs are primarily formed through the combination of aggregates and a hydraulic cement, such as Portland cement, which when mixed with water and allowed to cure provides a binder which binds the aggregates together to provide the relatively strong structural building unit. One of the detrimental characteristics of the typical CMU is the substantial porosity thereof, which allows water to readily be absorbed by the CMU and thereby flow through the CMU. This of course presents a substantial issue in rainy climates particularly where driving rain is common. In addition, while the use of light weight aggregates has allowed for the formation of CMUs which are of a lighter weight while maintaining a suitable compressive strength, there is still room for improvement in producing lighter weight CMUs. Further, there is substantial room for economically improving the compressive strength of CMUs. In addition, in climates which do not have a suitably high humidity, the curing of the CMUs typically uses steam or an artificially created high humidity environment which is heated in order to cure the CMUs within a reasonable period of time. Thus, there is also a need for a CMU material which will allow for the reduction of the curing time of the CMU.
The present invention provides improvements in these areas and other benefits which will be evident from the following description of the invention.